Looking in the Ontap SDK documentation for the lun-list-info API call, I can see several fields that might apply: "device-id", which is a 32bit integer value (and optional, it didn't show up in my tests), "serial-number", which is a string, and "uuid", which is also a string.
Arguably the easiest way to map from a LUN to the corresponding datastore is to use the VSC. That's manual though, no programming involved.
If you need a program or a script to do the mapping, Rick's answer already was correct:
A LUN's 'naa.' number IS its WWN, it's just another name.
To get the WWN, you use the serial-number of the LUN, convert it to its hexadecimal ASCII representation* and prefix it with "naa.60a98000". You can get the LUN serial-number using the 'lun-list-info' API call (to a filer, not to the DFM).
A volume has a UUID, though, which is its unique identifying feature.
To get from the LUN to the containing volume, you take the "volume-id" field from the same structure that has the LUN's serial number, and pass it to the "volume-list-iter-start" API call in its "object-name-or-id" parameter. The details are all in the API docs.
If you just need the name of the volume, that is also available from the structure returned by "lun-list-iter-next". The field is called "volume-name".
Which way you choose all depends on what you want to achieve in the end. Have fun and good luck!